


Seashells

by mygalaxyeyes



Category: Undertale (Video Game)
Genre: Aftertale Sans (Undertale) - Freeform, Crosstale Sans (Undertale), Crosstale Sans/Dreamtale Sans | Dream (Undertale), Dreamtale Nightmare Sans (Undertale), Dreamtale Nightmare Sans/Killer Sans (Undertale), Dreamtale Sans | Dream (Undertale), Dusttale Sans (Undertale), Dusttale Sans/Underswap Sans (Undertale), Errortale Sans (Undertale), Errortale Sans/Inktale Sans (Undertale), Gen, Horrortale Sans (Undertale), Horrortale Sans/Underlust Sans (Undertale), Inktale Sans (Undertale), Inktale Sans Has a Soul (Undertale), Killer Sans (Undertale) - Freeform, Multi, Reapertale Sans (Undertale), Underlust Sans (Undertale), Underswap Sans (Undertale)
Language: English
Status: In-Progress
Published: 2020-09-12
Updated: 2020-09-15
Packaged: 2021-03-06 22:14:05
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 4
Words: 2,638
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26416222
Author URL: https://archiveofourown.org/users/mygalaxyeyes/pseuds/mygalaxyeyes
Summary: Gift for BookwyrmFinallyGotAnAccount, when I told them I'd write a mer fic of my own. I've finally gotten around to it.
Relationships: Sans/Sans (Undertale)
Comments: 600
Kudos: 57





	1. Ch. 1 |  Shipwrecks.

**Author's Note:**

  * For [BookwyrmFinallyGotAnAccount](https://archiveofourown.org/users/BookwyrmFinallyGotAnAccount/gifts).



"Psst!"

A nudge to his tail, but Cross did not budge. He snuggled further into the purplish pink tentacle that was loosely wrapped around his waist, yawning softly. A few bubbles escaped his mouth, floating up into the ocean sea.

He was nudged again, this time a bit harder. Cross's eye sockets opened this time, glaring at the grinning merskele in front of him. "What do you want Killer? I'm trying to sleep." He was about to turn to nuzzle back into Fresh and go back to sleep, but then Killer spoke. "I found a shipwreck nearby. Wanna come with to go explore?"

He really should say no, but he loved exploring! Carefully, he wiggled out of Fresh's tentacle and follows his brother. Killer grins at him, and then bolts off quickly. Cross swims after him.

Within minutes — or at least what felt like minutes, they arrive at a shipwreck. The ship is huge! Cross' eyelights glint with astoundment, before he swam ahead. This was so exciting! Still... They'd probably get in trouble for wandering off on their own, but that thought didn't cross his mind.

"Cross! C'mon, wait up!" Killer swam after the younger merskele, huffing under his breath. This was his fault that Cross was really excited about exploring a shipwreck.

... Error was going to have his tail for this.

But they weren't alone, they were with each other. So therefore, they weren't breaking the rule of, _**don't go anywhere alone.**_

Cross darted to the inside of the ship. The ship itself wasn't anything special — maybe it was a pirate ship? It certainly wasn't big enough to be a cruise ship. But he spotted some seeweed, making his heterochromatic eyelights widen.

_"Bubba?! Momma? D-daddy…?" He couldn't get out. His tail was completely stuck in the seaweed that he had tried hiding in, along with a fin of his. He couldn't get out. He'd cut up his face on a really sharp rock earlier, and it really hurt. Surely it would leave a mark. Perhaps a purple one, since it was the color of his rare blood._

A whimper escaped Cross' mouth at the memory, reminding him that his blood family had indeed abandoned him. It took him awhile to register that, even when Error and Geno took him in, brought him to the rest of their little school. At the time, the only other ones were Killer, Dust, and Horror. He was terrified! And the memories that the seaweed brought... They were anything but pleasant.

Cross quickly darted out, before he crashed right into Killer, making him wince. And if it hadn't been for the older merskeleton grasping onto his wrists, he would have fell onto the deck of the ship.

"Gee and here I thought," Killer had started. But then he stopped, staring at Cross. "Rossy! You're shaking!" He was quick to tug him into a hug. For once, Cross didn't object to Killer's hugs. He really needed it right now.

"What happened?"

Cross was silent. The worry in Killer's voice made something tug and weigh down the younger mer's soul. And yet, he still worked up the courage to stutter out a reply. "I-i saw s-some seaweed."

Any other mer may have laughed. A merskeleton, afraid of seaweed? But Killer and the rest of their family know about how Cross was stuck for days in that seaweed, unable to get out. So its perfectly reasonable.

Killer sees lights coming from above, and lets go of the hug. He starts swimming for the lights, making Cross curious.

He follows after Killer, quick to keep his brother in his line of vision.


	2. Ch. 2 |  Purple and Yellow

He pokes his head above water, the sudden air felt very cold on his ribcage, and his natural ectobelly that started from the start of his tail until it reached just below his ribcage. It was a smooth, and rather vibrant persian red.

His tail was a grey blue, with large black rings decorating it. Inside those black rings were smaller persian red circles. He had what land dwellers described as ‘fin ears,’ although every merskeleton that he knew had them. His were also grey blue like his tail.

He glanced over at Cross, to see him already swimming ahead to get a look at the noise coming from the land. The younger mer's orchid purple ecto seemed to glow in the early hours of the morning. This was one of the reasons why they weren't allowed to go alone — mers were often wanted for their beautiful ectos. Mostly so they could be put on display in stupid aquariums.

Another reason why they had to stick together, was that it was extremely uncommon for mer to live in shallow waters, they were more common in the deeper waters. But... Schools of mer were usually larger than what they had in numbers. Usually there were twenty or more in a school, but the school that Error and Geno had formed was considerably smaller in size.

That's why it was a good idea to live in the abandoned reef that they lived in. Seaweed grew nearby (much to Cross's dismay), so it was rather easy to build nets to catch fish to eat. It worked, considering Geno and Horror had injuries that slowed them from hunting.

Snapping out of his thoughts, he quickly followed Cross, only to see Cross lifting his head above an edge that lead to the town. He followed his brother's lead, lifting his head to peak at the edge.

A group was hanging out was nearby, sitting down and laughing — but why were they hanging out so early in the morning?

One of them wore an amethyst purple tunic, with silver accents. On the collar of his tunic were two white crescent moons, on each side. He wore knee high purple tie up shoes — Killer thinks that Reaper has called them converse, if he remembers correctly. His pants (did Reaper call them denim or jeans?) were a soft blue, much softer than the grey blue color of his tail and ears. His eyelights were a beautiful shade of purple.

There were others, but... They didn't really catch his attention. Not like the one in the purple. One of the other skeletons — one with two differently colored (and differently shaped) eyelights looked in their direction, and that was when he and his brother ducked so that they were out of sight.

"What was that?" He heard one voice ask. It was melodically soft. He and Cross exchanged looks, and only then did he notice that Cross's cheekbones were flushed with a vivid purple. He was... Blushing?

"Probably a human trying to play a trick on us monsters again. Don't mind them brother," he heard a slightly different voice this time. A little similar to the first voice they heard — soft voiced, but this one was a little rougher.

"Ah! What if it was a mermaid?!" This voice sounded higher, but it certainly wasn't squeaky. He heard a deeper chuckle.

"Merskeletons and octoskeletons live in deeper waters, Blue. So while its a possibility.. Its highly unlikely," the rough sounding voice was heard again.

He and Cross shared a look. Killer nodded, before they quietly slipped back into the water. They started to swim back in the direction of the reef.

_God they were in so much trouble when they got home._


	3. Ch. 3 |  Busted

Error was pacing, which was never really a good thing. But it was better than his little brother racing off. Geno sighed, a hand rubbing the side of his skull. How long had those two been gone for? No one else was up when they left, so they didn't know.

Fresh and Horror — who were usually really talkative, were silent. Their gaze on the pacing mer that was their leader. Geno looked over at Dust, to see him hugging himself. Rocking himself back and forth, and by the plumish purple water around him — he guessed that he'd been crying. He saw Horror swim over and wrap Dust in a hug though, so... He stayed by his brother, in case Error needed him.

_It was easy to get lost in the deep sea, that's why merskeletons usually stayed close to their school. Though... Geno had accidentally wandered away from his own, and had gotten lost. It was dangerous to get lost im the deeper parts of the ocean, but luckily he was fast enough to hide when he could._

_Though, his tail and ears definitely made him stand out. They were a mixture of berry red and white, and were fairly visible from a couple miles away._

_He'd been hiding behind a rock, as soon as he saw a great white shark approaching from the distance. He stayed behind the rock, in fear that the shark would find him. He wished he would have stayed closer to his mother and his little brother as they were swimming, then this wouldn't of happened. He was fourteen! He should have been a faster swimmer!_

_"Psst," said a low voice that sounded way too close. He looked over, and next to him was another merskeleton! He blinked, biting his tongue so he would not let out a loud, startled yelp._

_This other mer had a black tail, with Egyptian blue stripes decorating his tail. His ears were mostly black, with a couple of Egyptian blue spots on them. His ecto was also that same color blue. His eyelights did not show, and he wore some kind of weird hood over his skull, and it was tied together in some sort of bow around his ribcage. In a way, he was kind of attractive._

_Geno glared at this mer, despite the fact he looked kind of cute. The merskeleton grinned at him though, making Geno stutter._

_What the heck?_

_"I'm Reaper," he introduced himself. Geno looked around with his eyelight before he finally met Reaper's gaze. "I'm Geno."_

_"You're from old man Tavern's school, right?" Reaper asked, making Geno's socket widen. This guy knew the leader of his school? Nevertheless, Geno nodded. Slowly, and looking at Reaper with an uncetainity._

_"Ha. My old man is friends with Tavern. They've been looking for you," Reaper muttered. He looked out towards the open waters, before looking back at him. His hand outstretched itself, before he gave a soft, kind smile._

_"So, me and my school were gonna go eat the great white the adults killed, and then go meet up with yours. So what do you say?"_

_Gently, he grasped Reaper's hand and nodded._

Geno smiled to himself at the memory, a warm berry red blush flushing over his cheekbones. He touched over the battered scarf that Reaper had given him as a courting gift. It had been shortly before the boat incident, so they were able to exchange gifts as a way of courting each other.

He turned to go look at his brother, only to see him swiftly swimming ahead. Confused, Geno quickly followed him. He was a bit faster than his brother, but slowed for the point of Error not fretting over him.

Then he saw it. Killer and Cross.

"Where have you two been!?" Error shouted. Cross looked down, while Killer adverted his gaze awkwardly. Geno huffed.

"We were..." Cross started, but his mouth was immediately muffled by Killer's hand. He glared at Killer. "Killer." Geno warned. He may not have been their leader anymore, but like hell if he would let Killer get away with quieting Cross.

Killer grumbled something under his breath, before pulling his hand away. Cross looked unsure, keeping his mouth shut. "Come on honey, where did you guys go?" He kept his voice as soft as possible.

"Killer woke me up early to go explore a shipwreck, and then we went up to the surface, and then back here." Error's glare shifted from both of them, to Killer. Geno nudged him in the ribcage — being gentle but firm about it.

Error seemed to get the memo, because then he rolled his eyelights and softened his glare. "Alright you two, come on back and then we'll discuss _both_ of your punishments. Killer, you should know better than to go off when barely anyone is awake. And Cross, you're old enough to know better."

Geno sighed, beginning to swim back to the reef. He was followed by his blood brother, and then their younger brothers.


	4. Ch. 4 |  The Deep

When you have a school of very powerful mers, you get away with small numbers. Though these days, he was often grumpy and preferred to either hunt alone, sleep, or spend time with his lover in the more shallow waters.

"Its like you're brooding," Red joked one day. He looked up, and sent the other mer a glare. "I am not brooding Red. That requires the _last_ step of the more extreme version of courting, which the first step hasn't even been been thought of being considered yet. Geno's not ready yet, and I respect that," he growled out.

"Oh, so you're just moody," Color commented. Reaper merely gave a soft grunt in response, curling up his tail on the ground of the cavern. The cavern was where his school lived. Unlike Geno and the others who lived in shallow waters, they needed a more secluded home to protect them from sharks and other deadly creatures when they slept.

"What are you guys up to now-" He opened his sockets a bit to see Sci — Red's mate, swimming over. He saw Red's cheekbones flush a crimson red. Where was Respite and dad when he needed them? He hated this teasing.

"They won't stop teasing me," Reaper muttered out. He turned on his other side, not wanting to look as Red and Color glared at him. All while Sci lectured them.

"Boys!" His father's voice made him get up, and swim over to the entrance of the cavern. His father and his brother Respite were carrying a mer inside.

Their tail was a soft floral purple, with small black vertical lines decorating it. Their ecto stomach and ears were also floral purple, but they were missing the black lines that his tail had. They had a scar going vertical against their right eye socket. It looked rather fresh.

Reaper frowned, starring at the duo. "What happened," he forced himself to move. Why was he so sluggish lately? Someone must have noticed, because Color was pulling him away before his sockets could grow heavy.

"By the way you've been acting, one could _think_ you and Geno took it to the next level," Color left, carrying him back to where Reaper usually slept.

He smacked Color in the face with his tail. "Well we didn't."

"How did you get with someone like Geno," he watched as Color's skull flared a brilliant orange. If he had eyelights, he would have rolled them far into the deep areas of his skull. "Well you see dear Color, we were attracted to each other, and started exchanging gifts." His voice dripped with sarcasm.

 _"That's not what I freaking meant,"_ Color huffed. Reaper chuckled in amusement, barely hiding a smirk. Color refused to say ‘bad words,’ despite that he was an adult. Color was twenty-three, the same age as Killer, but he insisted on no profanity. Perhaps maybe that's why he was good company when their little school met up with Geno and the others. 

Because Color didn't swear, which was great to Error, Geno and Horror. _"Killer gets into enough trouble, imagine what would having a vocabulary with swear words would do,"_ Geno had told him when he noticed Color did his very best not to swear.

"Put me down." He huffed, but he instantly regretted it. Color dropped him on the ground, covered in shark bones. He glared at Color, a scowl working its way onto his mouth.

_All hope for mercy is lost._


End file.
